1. Field of the Invention
The subject matter disclosed herein relates generally to methods and apparatus for review of medical imaging exams, and more particularly to methods and apparatus for delineation of vasculature in a region of interest in an anatomical region of a patient.
2. Description of Related Art
Blood vessels in the vasculature typically aid in the transportation of blood to various parts of the body. However, when a large artery in the vasculature is blocked by blood clots or other particles, the amount of blood supplied to the tissue may be insufficient, eventually causing tissue to die. For example, the presence of plaque restricts blood flow, damages the blood vessel wall and and/or promotes blood clot formation. In addition, calcification of blood vessels occurs where lipids accumulate in the blood vessel wall leading to hardening of the arteries. Also, an embolus in a blood vessel may cause severe dysfunction of an organ, which may be fatal if undiagnosed and/or untreated. For instance, blockage of the internal carotid artery may reduce blood supply to the brain, causing a stroke. Additionally, the function of the arteries in the lungs is to carry enough blood containing oxygen and nutrients to keep the lung tissue healthy and to carry carbon dioxide to the lungs for removal from the body. However, when a pulmonary artery is blocked by an embolus, plaque or calcification, the amount of blood supplied to the lung tissue may be insufficient, eventually causing tissue to die. Hence, it may be desirable to delineate vasculature in an anatomical region from surrounding background to aid in enhanced detection of disease states, if any.
Traditionally, an X-ray radiograph has been employed as a diagnostic tool for the purpose of detecting disease in humans. By way of example, a chest X-ray radiograph may be employed to aid a clinician in the detection of disease in the lungs. As noted hereinabove, it may be desirable to delineate vasculature in an anatomical region to enhance ease of detection and/or diagnosis of disease states. For example, it may be desirable to delineate vasculature in the lungs from the surrounding background to aid in the detection of any disease states in the lungs of the patient. However, delineation and reconstruction of curvilinear pulmonary vascular structures generally pose a greater challenge to image segmentation algorithms largely due to the fact that the sensitivity and selectivity of a single energy X-ray radiograph is arguably low for the extraction of vascular tree. Moreover, the pulmonary vasculature or vascular tree is known to be inherently complex with elongated shapes and multiple branches. In addition, given the microscopic distribution of pulmonary vascular structures, extraction of these vessels is a difficult and onerous task due to significant overlap of rib structures, which results in background noise and irregular shape detection. Furthermore, this low energy level of the chest X-ray radiograph may disadvantageously lead to missed detection of disease states, as it is difficult to identify a suspicious area in an extensive amount of data. In addition, confusion caused by branching points in the vasculature, veins, motion artifacts, partial volume and other pathologies may lead to misdiagnosis.
It may therefore be desirable to develop a robust technique and system for delineation of vasculature from the surrounding background that advantageously facilitates substantially superior detection of disease states in the vasculature, while simultaneously maintaining the number of false-positives to a minimum. In particular, there is a need for a system that is configured to facilitate the delineation of image data representative of pulmonary vasculature using digital X-ray image data, thereby enhancing ease of detecting disease states in the pulmonary vasculature and simplifying the clinical workflow of the diagnostic imaging system.